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Lithium Ion Battery Safety

How to Prevent Lithium Ion Ebike Battery Fires

Tips on Charging, Storage, Usage, and Stopping a Fire

Preface

Almost all electric bicycles are powered by lithium-ion batteries. These batteries have a very high energy density, which allows ebikes to be relatively low weight yet have a long range. With all their advantages, a big challenge with Lithium battery safety is the risk of fire from poorly built batteries, chargers, or user-error. 

In New York, 121 fires were attributed to Li-ion batteries between Jan 1, 2022- Aug 3, 2022 and lithium-ion battery fires. These reports highlight the fact that with the growing popularity of electric-powered equipment (including ebikes), the risk of battery fires is also increasing. Statistically speaking, the failure rate for li-ion is rare, and most batteries are not inherently dangerous. Still, even one failure is too many.

On the supplier side,  we use the highest quality material in our batteries, such as branded LG, Panasonic, or Samsung li-ion cells. We do not use off-brand Chinese budget cells. We also design our batteries with overcharge, over-discharge, overcurrent, temperature cutoff protection, and other safety features.

We also believe it is very important to educate our customers regarding possible hazards and preventive measures they can take to ensure their safety.

The goal of the following information is to be a helpful guide for you. We will include tips on safely charging and storing your lithium-ion battery, plus what you can do in case of a fire emergency.

How to Safely Charge Your Ebike Battery

Most reported battery fires are caused during the charging of the batteries, especially when the batteries are in direct sun or lying on a blanket or carpeted floor which prevents air circulation. It is imperative that you follow these recommendations while charging your battery.

  • Always use our branded charger. If you are buying an aftermarket charger, make sure it has UL certification and the exact specifications as the original charger. DO NOT use a fast charger with a battery that is not designed for fast charging. Our batteries are designed for safe slow charging (5 to 8 hours to fully charge). This is the safest way to recharge a lithium battery.
  • Never place or charge the battery near a high-temperature source such as a heater. High temperatures can damage Li-ion cells and cause thermal runaway events.
  • Do not charge the battery in direct sunlight, and do not allow direct sunlight on the charger.
  • Never place the charger or battery on or near a flammable material such as wooden furniture or building structures. Always try to put the charger and battery on fire safe surfaces or spaces such as a concrete floor far away from anything that is combustible.
  • Never charge the battery with it or the charger on a blanket or carpet.
  • Charge in a well-ventilated area.
  • Always keep the battery in view when it is charging.
  • Turn off the battery when charging.
  • As is normal, the charger will get warm during charging, but the battery should never get hot (use your hand to feel the warmth). Disconnect the battery if it is getting hot.
  • Never charge in sub-zero temperatures as it may cause dendrite growth on the Li-ion cells, leading to short circuits and, consequently, fire hazards.
  • Do not leave the battery on charging overnight even though it is designed to automatically stop charging when the battery is full. Out of an abundance of caution, charge during the day when you can check on it.
  • As a further precaution, keep a smoke alarm close to the battery.
  • In case of fire, the first few seconds are critical so that you can put out the fire before it gets out of control. Response procedures are described below.

In Case of an Emergency

Observing the recommendations in the previous sections will significantly decreases the chance of a fire emergency. Nevertheless, it is important to familiarize yourself with the following steps in case of emergency.

  • Use a quality approved fire extinguisher.  Since fires caused by Lithium-ion batteries are Class B fires, you should have a standard ABC or dry chemical fire extinguisher. The fire extinguisher needs to be a type “2-A:10-B:C extinguisher. They are commonly available at hardware and department stores and many online stores.

 

  • Please watch this video so you know how to use this type of extinguisher. https://www.youtube.com/watch?v=usM6PAgHFJA
  • Pull out the safety pin to use the extinguisher
  • Target the nozzle at the base of the fire
  • Squeeze the handle firmly
  • To ensure that you put out the fire wholly and correctly, sweep the nozzle back and forth across its base.
  • Take the battery out of the building. If you suspect something is wrong (e.g., the Battery case getting warm, liquid leaking, or the battery making noises), you should put it outside in a safe, open space and wait for the battery to go back to normal. Please note, do not try to handle the battery that has caught fire or leaking fluids as it can be hazardous to you.  
  • Even after you put out the battery fire, continue to watch it as it is possible that the internal cells can ignite again.
  • Call the fire department. Li-ion battery fires can be thermal runaway events. Subsequently, ebike battery fires can pose several hazards, like poisonous smoke, flames, and metal projectiles. After taking the necessary measures explained above, if you cannot contain the fire, you should call the nearest fire station in your area without delay, and follow their instructions.

Proper Li-ion Battery Storage

  • When storing the battery for a prolonged period such as through the winter, charge batteries to about 60%.
  • Avoid storage in extreme temperatures or high moisture.
  • Do not store batteries in the trunk of your car where it can get hot or freeze.
  • Do not use batteries that are dropped, punctured, crushed, or damaged.
  • Do not store or charge batteries near a single exit point.

Safe Usage of Li-ion Battery

  • If a battery starts smoking, emitting unusual noises, or showing signs of melting, stop using it immediately and place the battery in a safe place.
  • Stop using the battery if you see a drastic change in voltage/performance.
  • If you dropped the battery case/bike in the water, have it evaluated by a professional before you use the battery. (The presence of moisture inside the battery case indicates that water has infiltrated the case and can cause a short circuit). So we don’t recommend riding your ebike in the rain. A certain amount of casual moisture is OK, but be careful not to remove your battery if you are washing your ebike.
  • Always use the battery with the product it came with; do not use it for any other ebike.

What Safety Features Included

Recent progress in BMS (Battery Management Systems) has led to better control of the battery packs in ebikes from several perspectives, especially while charging and discharging. We provide ebike batteries that meet or exceed industry standards. Following are some of the safety features of our batteries.

  • Charging Protection (Voltage and Current) – Our batteries cut off charging if the charging voltage or current gets higher than the defined range. This ensures that charging is discontinued in case of any fault.
  • Cell Balancing – Cell balancing and cell balancing cutoff improves the available capacity of the battery and reduces the chance of any one of the cells deteriorating which would cause it to get hotter than the others.
  • Discharge Protection (Voltage and Current) – During the operation of the battery and ebike, the voltage and current value are measured; if the voltage gets too low or the current value gets too high, the BMS cuts off the battery for safety reasons. This can happen on rare situations such as prolonged high-energy output under heavy load climbing a hill under full throttle power.
  • Temperature Cutoff Protection – Similar to Discharge Protection, our Li-Ion batteries include a temperature cutoff protection mechanism that shuts down the battery when the temperature value exceeds the safe limit.
  • Short Circuit protection – Short-circuit in Li-ion batteries is always dangerous. It may damage your battery and decrease its lifecycle at best. And at worst, a short circuit can lead to a battery fire or burst, causing injury, property damage, or even death. Our batteries include short circuit protection designed to monitor the battery’s voltage to prevent hazardous situations arising from short circuits in the batteries.

Conclusion

Li-ion batteries are widely used in ebikes today. Ebikes made by reputable companies that stand behind their products are safer than ever before. Though these batteries are not inherently dangerous, some ebike user’s inappropriate treatment can lead to fire incidents. It is our goal to minimize any issues with batteries by using quality cells, building in safety mechanisms, describing proper charging procedures, and educating our customers about how to extinguish a battery fire if it ever happens.

Ultimately, it is the customer’s responsibility to follow these recommendations. Get an approved extinguisher, follow proper charging and storage methods, and know how to put out a battery fire if one occurs.

If you have any questions about battery safety or emergency procedures, please don’t hesitate to contact us